1. Field of the Invention
The present invention relates to image processing method and apparatus, and more particularly, to image processing method and apparatus for reducing image crosstalk.
2. Description of the Prior Art
FIG. 1 depicts a diagram showing relations between active pixel area (image pixel area), horizontal blanking area, and vertical blanking area in the prior art. And FIG. 2 depicts a timing sequence diagram of image transmission in the prior art.
Please refer to FIG. 1, an image frame Fr usually comprises a first active pixel area AP1 which consists of multiple active pixel rows such as AP11 and AP12 (only two rows are shown). Besides, in order to guarantee the success of image transmission, a first horizontal blanking area HB1 and a first vertical blanking area VB1 are provided switching lines and frames during the image transmission. The first horizontal blanking area HB1 comprising multiple horizontal blanking pixel rows such as HB11 and HB12 (only two rows are shown) is vertical for the switches between active pixel rows. The first vertical blanking area VB1 comprising multiple vertical blanking pixel rows such as VB11 and VB12 (only two rows are shown) is vertical for the switches between image frames.
Please refer to FIG. 2, the image frame Fr is conventionally transmitted according to a first timing signal PCLK1. The first timing signal PCLK1 comprises at least one first active pixel time period A1, at least one first horizontal blanking time period H1, and a vertical blanking time period V1. During each of the first active pixel time periods A1, one active pixel row is transmitted. After one active pixel row is transmitted, no data is transmitted during the adjacent first horizontal blanking time period H1, and then the transmission of a next active pixel row follows. Take the example shown in the FIG. 2, the active pixel row A11 is transmitted during the first active pixel time period A1. After that, no data transmission happens during the adjacent first horizontal blanking time period H1. And it follows that the next active pixel row A12 is transmitted during an adjacent first active pixel time period A1. The rest of active pixel rows are transmitted in similar way. After all active pixel rows are transmitted, data transmission is paused during the first vertical blanking time period V1. And then, the transmission of next image frame follows. Therefore, the number of pixels corresponding to each of first active pixel time period A1 is equal to the number of pixels in each of the first active pixel rows such as AP11 and AP12. The number of pixels corresponding to the first horizontal blanking time period H1 is equal to the number of pixels in each of the first horizontal blanking pixel rows such as HB11 and HB12. The number of pixels corresponding to the first vertical blanking time period V1 is equal to the sum of numbers of pixels in all of the first vertical blanking pixel rows such as VB11 and VB12.
In details, a backlight module of a display only is turned on during first vertical blanking time periods in some applications such as simulated impulse type liquid crystal displays or 3D displays. In other words, after a first image frame (i.e., the active pixel area) is already shown on the display, the backlight module of the display is turned on at a timing point within the first one of the first vertical blanking time periods. Until the end of the first one of the first vertical blanking time periods, the backlight module of the display is turned off. Following that, a second image frame is shown on the display. Similarly, the backlight module of the display is turned on at a timing point within the second one of the first vertical blanking time periods. The backlight module of the display is turned off while the end of the second one of the first vertical blanking time periods. And the described cycle goes on and on. User's eyes perceive the image frame while the backlight module is lighted. Since some characteristics carried by liquid crystal itself, a transformation between different pixel data (for example from pixel data A to pixel data B) needs some time for raising or descending of signal voltage levels. Therefore what eyes perceive is a mixture of pixel data A and pixel data B in a certain proportion. Ideally, the proportion of A versus B is 0% versus 100%, i.e., no prior image frame should be perceived by user's eyes. However, due to the characteristics of liquid crystal, the ideal situation may not happen as wishes. Therefore the proportion of data mixture phenomenon is called “crosstalk.”
From the above it is clear that prior art still has shortcomings. In order to solve these problems, efforts have long been made in vain, while ordinary products and methods offering no appropriate structures and methods. Thus, there is a need in the industry for a novel technique that solves these problems.